MODELLING OF DISLOCATION MULTIPLICATION AND ASSOCIATED MINORITY CARRIER LIFETIMEREDUCTION DURING DIRECTIONAL CRYSTALLIZATION OF SILICON INGOTS

摘要

Multi-crystalline silicon ingot casting using directional crystallisation is the most cost-effective technique for the production of Si for the photovoltaic industry. Non-uniform cooling conditions and a non-planarity of the solidification front result, however, in the build-up of stresses and plastic deformation. Known defects, such as dislocation densities and residual stresses can then occur and reduce the quality of the produced material. Numerical simulation, combined with experimental investigation, is therefore a key tool for understanding the crystallisation process, and optimizing it. The purpose of the present work to is present an application of a dislocation generation model to the crystallization and subsequent cooling of silicon ingots in the experimental furnace at SINTEF. The present work is a follow-up to the analyses presented in References [1,2].